Antennas are deployed in many remote sensing, communications, and other applications in which characteristics of a signal of interest received by an antenna are used to identify characteristics of an environment, convey information, etc. In many cases, the environments in which antennas are deployed for such purposes are also subject to noise and interference from various sources of electromagnetic (EM) emission. When noise and interference are received contemporaneously with a signal of interest at an antenna, it can be difficult to isolate the signal of interest from the noise and interference in the output of the antenna. Identification of a time period during which the signal of interest is present in the output of the antenna can aid in processing of the antenna output to isolate the signal of interest. Conventionally, power threshold detectors that are tuned to specific characteristics of the signal of interest and interfering signals in the output of the antenna are used to identify a time period during which the output of the antenna includes the signal of interest. Conventional power threshold detectors therefore require advance knowledge of expected signal parameters of the interfering signals and the signal of interest.